Chemopreventive effects of raw and roasted oat flakes after in vitro fermentation with human faecal microbiota

Abstract

The aim of the present study was to analyse chemopreventive effects of oat flakes under consideration of processing. Thin and thick flakes were roasted and subjected to an in vitro digestion and fermentation. Fermentation supernatants (FS) were characterised and chemopreventive effects were analysed in LT97 colon adenoma cells. Compared to the fermentation control, pH values were decreased (from pH 6.3 to pH 5.0) and concentrations of SCFA, in particular butyrate, were increased in oat FS (2.6-fold, on average). Ammonia levels were not altered. Oat FS significantly decreased cell growth time- and dose-dependently. Caspase 3 activity was significantly increased (9.7-fold, on average). Oat FS slightly increased the mRNA expression of CAT (2.0-fold), SOD2 (1.7-fold) and GSTP1 (2.8-fold), on average, while GPX1 mRNA (0.3-fold) was decreased. The results indicate a chemopreventive potential of in vitro digested oat flakes regarding colon cancer development mediated mostly by growth inhibition and apoptosis, unaffected by roasting.

Keywords:

• Oat
• β-glucan
• chemoprevention
• colon cancer
• roasting

Acknowledgements

The authors thank Peter Kölln GmbH & Co. KGaA for allocation of raw oat products. The authors also thank Probat-Werke von Gimborn Maschinenfabrik GmbH for roasting the oat products, especially Thomas Koziorowski and Thomas Elshoff. Furthermore, we would like to express our gratitude to Sandra Hebestreit from the Department of Nutritional Toxicology for her excellent technical assistance.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This IGF Project (AiF 19351 BR) of the FEI (Research Association of the German Food Industry) was supported via AiF (German Federation of Industrial Research Associations) within the program for promoting the Industrial Collective Research (IGF) of the German Ministry of Economic Affairs and Energy (BMWi), based on a resolution of the German Parliament.